The next may be called external auricular ; they ascend to the anterior part of the car tilaginous tube of the ear, concealed by the temporal artery, attach themselves to the tube in front, and are distributed to the integuments of the concha.
Lastly, the superficial temporal nerve emerges from the parotid gland, beneath the root of the zygoma, between the condyle of the jaw and the cartilaginous tube of the ear, in company with the temporal artery, and concealed by it : it then changes its course and ascends with the artery behind the zygoma and in front of the ear, upon the temple: there it emerges from beneath the artery, posterior to it, and divides into branches, which become subcutaneous, run superficial to the fascia and the artery beneath the subcutaneous cellular structure, and are ultimately distributed to the integument of the temple : their number is two or three; they may be distinguished into anterior, middle, and posterior, and they are destined to the corresponding parts of the temple : they correspond in their course, but by no means regularly or strictly so, to the branches of the temporal artery, from which they are separated by the fascia.
Of the two terminal branches of the third division, the larger one, the inferior maxil lary or dental, descends outward to the upper orifice of the inferior maxillary canal. In its course it passes always behind the inter nal maxillary artery, and soon glides between the internal lateral ligament of the temporo maxillary articulation, and the ramus of the jaw, descending in front of the anterior margin of the ligament, which thus becomes interposed between it and the lingual branch, and also be tween it and the internal pterygoid muscle, from the pressure of which the ligament is considered toprotect it. In that situation it is joined by the inferior dental artery, a branch of the internal maxillary given off between the ligament and the jaw, which accompanies it through its further course. It next enters the canal, and is trans mitted through it downward, forward, and inward toward the chin, beneath the sockets of the teeth ; having reached the termination of the canal, it is reflected upward and outward through the mental foramen, and escapes from the canal upon the lateral and superficial surface of the jaw, at either side of the chin ; at its exit it is beneath the second bicuspid tooth of the lower jaw, and covered by the muscles of the lip : it then terminates by dividing into two branches, called inferior labial nerves, external and internal. The branches of the inferior
maxillary are as follow :—presently after its origin it gives off the branch by which the lingual branch and the inferior maxillary are connected, and which completes the loop through which the internal maxillary artery passes; also the branch which forms a root of the superficial temporal nerve. Next, imme diately before entering the dental canal, it gives off a long slender branch, denominated inylo hyoid nerve; this branch descends forward and inward along the inside of the ramus of the jaw, between it and the internal pterygoid muscle, and lodged in a groove upon the sur face of the bone, which leads in the same direction, and is occasionally in part a bony canal ; it is covered in the groove by a prolon gation of the internal lateral ligament, and escapes from it inferiorly in front of the insertion of the internal pterygoid muscle and beneath the lingual branch ; it then passes beneath or external to the mylohyoid muscle, between the submaxillary gland and the internal surface of the jaw, gains the surface of the muscle itself and runs forward and inward above the super ficial portion of the gland, between it and the muscle, and accompanied by the submental artery; finally, it divides into a leash of branches. Of these one is sometimes destined to the sub maxillary gland ; two or three are distributed to the mylohyoid muscle; another to the anterior belly of the digastric, and the last passes first between the anterior belly of the digastric and the mylohyoid, gives filaments to the muscles in its passage, then ascends upon the chin internal to the belly of the digastrie, and is consumed in the depressor labii muscle.